During the past year, to put our photodensitometry system using a laser light source into practice, some experiments have been performed.The fundamental design of the equipment was partially changed : PIN photodiode and a homemade amplifier were replaced with commecially available ones. As Visual Basic, which is superior in its user interface, was found to be available on MS-DOS, programming by Quick Basic was changed to programming by Visual Basic. With regard to the conditions of the film scan, the diameter of the slit in the apparatus reciving light was temporarily set at 300mum, and the minimum moving distance of film was fixed at 100mum. It was also confirmed that other parameters could be determined in constant relation. With this system, the concentrations at an arbitrary point in the film, on a line between two pionts, and in a rectangular area could be measured. The results of the measurements obtained were saved as text-data.Because of limitations in the main memory volume (640KB) of the personal computer and in programming in arrangements of less than 64KB, FFT of one or two dimensions and processing of various data were used in combination with other software such as graph-softwafe (N graph) specified for the PC-98 and image processing software (NIH Image). Further accumulation of clinical data including application to microdensitometry is expected.